The present invention relates generally to field of computer vision. More specifically, the present invention is directed to a method using a reference cube for capturing 3D geometry.
The use of a series of images from a video camera to determine 3D geometry is known in the field of computer vision as the shape from motion problem. Shape from motion is divided into two more fundamental problems such as determining point correspondence, and the application of shape from motion algorithms. Current shape from motion algorithms uses orthographic factorization or nonlinear optimization techniques. The factorization methods use orthogonal projection models. Since a video camera image is clearly a perspective view, these methods are limited to capturing far away objects where the effects of perspective are diminished. The nonlinear optimization methods are iterative and require good initial estimates in order to ensure convergence, thus these methods may not be suitable for real time applications.
The projected edge vectors from a viewpoint to a video image of the reference object on a projection plane are determined. The reference object has three orthogonal edges, and the projected edge vectors correspond to edge vectors of the reference object. The orthonormal basis vectors for subspaces are generated using the projected edge vectors and a vector from the viewpoint to an intersection of the projected edge vectors. The directions of the edge vectors corresponding to the projected edge vectors are calculated. The distance between the reference object and the viewpoint is calculated. Using this distance, the coordinates of the reference object are determined.